-------------------------------------------------------------------
-- Main Table
-------------------------------------------------------------------
local LoadingScreensInfo = {
    -- Vanilla
    -- [1]  = { weight = 10, requiredEventFlag = 0 },           -- Limgrave: Third Church of Marika
    -- [2]  = { weight = 10, requiredEventFlag = 0 },           -- Limgrave: View of the Erdtree
    -- [3]  = { weight = 10, requiredEventFlag = 0 },           -- Stormveil: Throneroom Statue of Godfrey
    -- [4]  = { weight = 10, requiredEventFlag = 0 },           -- Farum Azula: Maliketh Bossroom
    -- [5]  = { weight = 10, requiredEventFlag = 0 },           -- Limgrave: Divine Tower of Limgrave
    -- [6]  = { weight = 10, requiredEventFlag = 0 },           -- Limgrave: Nomadic Merchant
    -- [7]  = { weight = 10, requiredEventFlag = 0 },           -- Raya Lucaria: Debate Parlor
    -- [8]  = { weight = 10, requiredEventFlag = 0 },           -- Mountaintop of the Giants: Giant's Corpse
    -- [9]  = { weight = 10, requiredEventFlag = 0 },           -- Roundtable Hold: The Round Table
    -- [10] = { weight = 10, requiredEventFlag = 0 },           -- Limgrave: Ruins with a Stake of Marika
    -- [11] = { weight = 10, requiredEventFlag = 0 },           -- Limgrave: Blaidd
    -- [12] = { weight = 10, requiredEventFlag = 0 },           -- Mt. Gelmir: Abductor Virgins
    -- [13] = { weight = 10, requiredEventFlag = 0 },           -- Leyndell, Royal Capital: The Queens Bedchamber
    -- [14] = { weight = 10, requiredEventFlag = 0 },           -- Weeping Peninsula: Walking Mausoleum
    -- [15] = { weight = 10, requiredEventFlag = 0 },           -- Redmane Caste: Castalian Jerren
    -- [16] = { weight = 10, requiredEventFlag = 0 },           -- Liurnia: Wraithcaller Rider
    -- [17] = { weight = 10, requiredEventFlag = 0 },           -- Stormveil: Main Gate
    -- [18] = { weight = 10, requiredEventFlag = 0 },           -- Jarburg: Living Jars
    -- [19] = { weight = 10, requiredEventFlag = 0 },           -- Nokstella: Giant Skeleton
    -- [20] = { weight = 10, requiredEventFlag = 0 },           -- Volcano Manor:bLady Tanith
    -- [21] = { weight = 10, requiredEventFlag = 0 },           -- Limgrave: Caravan
    -- [22] = { weight = 10, requiredEventFlag = 0 },           -- Limgrave: Guardian Golem
    -- [23] = { weight = 10, requiredEventFlag = 0 },           -- Catacombs: Erdtree Roots
    -- [24] = { weight = 10, requiredEventFlag = 0 },           -- Abyssal Woods: Midra's Manse
    -- [25] = { weight = 10, requiredEventFlag = 0 },           -- Belurat: Main Gate
    -- [26] = { weight = 10, requiredEventFlag = 0 },           -- Cathedral of Manus Metyr: Emyr's Throne
    -- [27] = { weight = 10, requiredEventFlag = 0 },           -- Jagged Peak: Jagged Peak Drake
    -- [28] = { weight = 10, requiredEventFlag = 0 },           -- Ruins of Rauh: Pond
    -- [29] = { weight = 10, requiredEventFlag = 0 },           -- Black Keep: Burning Boats
    -- [30] = { weight = 10, requiredEventFlag = 0 },           -- Gravesite Plains: View of the Scadutree
    -- [31] = { weight = 10, requiredEventFlag = 0 },           -- Midra's Manse: Family Portrait
    -- [32] = { weight = 10, requiredEventFlag = 0 },           -- Scadu Altus: Furnace Golem
    -- [33] = { weight = 10, requiredEventFlag = 0 },           -- Cerulean Coast: Spirit Eel
    -- [34] = { weight = 10, requiredEventFlag = 0 },           -- Gravesite Plains: Miquella's Cross
    -- Modded
    [35] = { weight = 10, requiredEventFlag = 0 },          -- Gregory
}

-------------------------------------------------------------------------
-- Included Requirements
-- Only for HKS Nerds
-------------------------------------------------------------------------

local TraversePointerChain = 10000
local WritePointerChain = 10000
local ExposeDebugPrint = 10001
local GetEventFlag = 10003
local UNSIGNED_SHORT = 2
local UNSIGNED_INT = 4
local GAME_BASE = 0
local CHR_INS_BASE = 1
local CS_NOW_LOADING_HELPER = 0x3D60EC8 -- 1.16
local WORLD_CHR_MAN = 0x3D65F88 -- 1.16
local LOCAL_PLAYER_OFFSET = 0x1E508 -- 1.16
local CURRENT_MENU_LOAD_INDEX = 0xD0
local CHR_HANDLE = 0x8

function MENU_LOAD_ENTRIES(index)
    return 0x48 + (index * 0x4)
end

function AttachAfter(Function, Addition)
    local oldFunction = Function
    return function(...)
        local result = oldFunction(...)
        Addition(...)
        return result
    end
end

local _isLocalPlayer = nil
function IsLocalPlayer()
    if _isLocalPlayer == true then
        return TRUE
    elseif _isLocalPlayer == false then
        return FALSE
    end

    if env(IsCOMPlayer) == FALSE and SelfHandleAsParts() == LocalPlayerHandleAsParts() then
        _isLocalPlayer = true
        return TRUE
    end
    _isLocalPlayer = false
    return FALSE
end

function SelfHandleAsParts()
    local a = env(TraversePointerChain, CHR_INS_BASE, UNSIGNED_SHORT, CHR_HANDLE + 0x0)
    local b = env(TraversePointerChain, CHR_INS_BASE, UNSIGNED_SHORT, CHR_HANDLE + 0x2)
    local c = env(TraversePointerChain, CHR_INS_BASE, UNSIGNED_SHORT, CHR_HANDLE + 0x4)
    local d = env(TraversePointerChain, CHR_INS_BASE, UNSIGNED_SHORT, CHR_HANDLE + 0x6)
    return a, b, c, d
end

function LocalPlayerHandleAsParts()
    local a = env(TraversePointerChain, GAME_BASE, UNSIGNED_SHORT, WORLD_CHR_MAN, LOCAL_PLAYER_OFFSET, CHR_HANDLE + 0x0)
    local b = env(TraversePointerChain, GAME_BASE, UNSIGNED_SHORT, WORLD_CHR_MAN, LOCAL_PLAYER_OFFSET, CHR_HANDLE + 0x2)
    local c = env(TraversePointerChain, GAME_BASE, UNSIGNED_SHORT, WORLD_CHR_MAN, LOCAL_PLAYER_OFFSET, CHR_HANDLE + 0x4)
    local d = env(TraversePointerChain, GAME_BASE, UNSIGNED_SHORT, WORLD_CHR_MAN, LOCAL_PLAYER_OFFSET, CHR_HANDLE + 0x6)
    return a, b, c, d
end

-------------------------------------------------------------------
-- Actual Code
-------------------------------------------------------------------
local LoadingScreensPopulated = false
function LoadingScreenHandler()
    if not IsLocalPlayer() then
        return
    elseif LoadingScreensPopulated then
        MonitorLoadingScreenEventFlags()
        return
    end
    LoadingScreensPopulated = true

    if env(TraversePointerChain, GAME_BASE, UNSIGNED_INT, CS_NOW_LOADING_HELPER, CURRENT_MENU_LOAD_INDEX) ~= 1 then
        LimitLoadingScreenAmountHandler()
        return
    end

    PopulateLoadingScreens()
end

function PopulateLoadingScreens()
    local currentLoadingScreenTable = GetCurrentLoadingScreenTable()
    -- Get the last 5 played loading screens
    -- First loading screen on startup is on index 1
    -- In Lua, indices start at 1 instead of 0, meaning in this table we include index 2
    local lastFiveOld = {
        currentLoadingScreenTable[31],
        currentLoadingScreenTable[32],
        currentLoadingScreenTable[33],
        currentLoadingScreenTable[1],
        currentLoadingScreenTable[2]
    }

    local availableIndices = {}
    for index, info in pairs(LoadingScreensInfo) do
        if info.weight > 0 and (info.requiredEventFlag <= 0 or env(GetEventFlag, info.requiredEventFlag) == TRUE) then
            table.insert(availableIndices, index)
        end
    end

    if #availableIndices == 0 then
        act(ExposeDebugPrint, "[WARNING!] Not enough available loading screens to populate table. At least 1 need to be possible. Loading screens were not updated.")
        return
    end

    local used = {}
    for i = 0, 33 do
        -- Neccessary evil for making it so high weight loading screens dont get placed in index 0 or index 1
        -- If not the weight based priority system has no use because the high weight items will be at an index that
        -- require a full rotation before they show up.
        local index = i + 2
        if index > 33 then
            index = index - 34
        end

        local candidates = {}
        for _, idx in ipairs(availableIndices) do
            if not used[idx] then -- Exclude already added loading screens
                if i > 4 or Contains(lastFiveOld, idx) == FALSE then -- For first 5, exclude lastFiveOld
                    table.insert(candidates, idx)
                end
            end
        end

        local selectedIdx = 0
        if #candidates ~= 0 then
            -- Calculating total weight
            local totalWeight = 0
            for _, idx in ipairs(candidates) do
                totalWeight = totalWeight + LoadingScreensInfo[idx].weight
            end
            -- Weighted random selection
            local rand = math.random() * totalWeight
            local cumulative = 0
            for _, idx in ipairs(candidates) do
                cumulative = cumulative + LoadingScreensInfo[idx].weight
                if rand <= cumulative then
                    selectedIdx = idx
                    break
                end
            end
            
            used[selectedIdx] = true
        end

        act(WritePointerChain, GAME_BASE, UNSIGNED_INT, selectedIdx,  CS_NOW_LOADING_HELPER, MENU_LOAD_ENTRIES(index))
    end
end

function GetCurrentLoadingScreenTable()
    local _table = {}
    for i = 0, 33, 1 do
        table.insert(_table, env(TraversePointerChain, GAME_BASE, UNSIGNED_INT, CS_NOW_LOADING_HELPER, MENU_LOAD_ENTRIES(i)))
    end
    return _table
end

local monitoredFlags = nil
function MonitorLoadingScreenEventFlags()
    -- Collect all loading screens with requiredEventFlag > 0 and currently false
    if monitoredFlags == nil then
        monitoredFlags = {}
        for index, info in pairs(LoadingScreensInfo) do
            if info.requiredEventFlag > 0 and env(GetEventFlag, info.requiredEventFlag) ~= TRUE then
                monitoredFlags[info.requiredEventFlag] = index
            end
        end
    elseif next(monitoredFlags) == nil then
        return
    end

    -- Monitoring loop (call this function periodically, e.g., every frame or on event update)
    for flag, index in pairs(monitoredFlags) do
        if env(GetEventFlag, flag) == TRUE then
            local nextMenuLoadIndex = env(TraversePointerChain, GAME_BASE, UNSIGNED_INT, CS_NOW_LOADING_HELPER, CURRENT_MENU_LOAD_INDEX) + 1
            if nextMenuLoadIndex > 33 then
                nextMenuLoadIndex = 0
            end

            act(WritePointerChain, GAME_BASE, UNSIGNED_INT, index, CS_NOW_LOADING_HELPER, MENU_LOAD_ENTRIES(nextMenuLoadIndex))
            monitoredFlags[flag] = nil
        end
    end
end

local nextLoadingScreen = 0
function LimitLoadingScreenAmountHandler()
    if nextLoadingScreen ~= 0 then
        return
    end

    local currentTable = GetCurrentLoadingScreenTable()
    local currentIndex = env(TraversePointerChain, GAME_BASE, UNSIGNED_INT, CS_NOW_LOADING_HELPER, CURRENT_MENU_LOAD_INDEX) -- Range 0 - 33
    local _nextLoadingScreen = currentTable[currentIndex + 2] -- Not +1 because lua starts it's table index at 1

    if _nextLoadingScreen ~= 0 then
        nextLoadingScreen = _nextLoadingScreen
        return
    end

    act(WritePointerChain, GAME_BASE, UNSIGNED_INT, 1, CS_NOW_LOADING_HELPER, CURRENT_MENU_LOAD_INDEX)
    PopulateLoadingScreens() -- Since index will be reset to 1
    nextLoadingScreen = currentTable[1]
end

Update = AttachAfter(Update, LoadingScreenHandler)